What does this sign indicate?

• Slower vehicles should continue at their current speed.
• Slower vehicles must use designated turnouts to allow faster vehicles to pass.
  Explanation:

  "This sign informs slower-moving vehicles (such as trucks or vehicles driving at reduced speeds) that they should pull into designated turnouts to allow faster vehicles to pass safely."
• Slower vehicles must merge into faster traffic.
• Slower vehicles must stop and yield to faster traffic.